1. Field of the Invention
This invention pertains broadly to tools for determining the special relation of objects to other objects and particularly to the earth including attitude or orientation and more particularly still to so-called leveling of objects with respect to each other or to the earth.
2. Preliminary Discussion
Tilt or inclination sensing devices have been known broadly for many years and for many purposes. Early types relied upon sight estimation of angle from the orientation of bubbles or floats in a clear liquid such as ethyl alcohol or other clear liquid contained in transparent tubes, initially gently curved glass tubes but later plastic tubes, which are less subject to breakage, and later by electrical signals transmitted through a conductive liquid such as mercury or the like normally confined in a tubular pathway.
The use of bubbles of air confined in a gently curved tube is frequently referred to as use of a so-called spirit level. Another early type of level detector depended upon the principle of a pendulum either visually monitored or electrically monitored. Gas bubble and pendulum type levels are generally lacking in sensitivity or readability, although the reliability of such instruments is fairly good when undamaged. Electrical or electronic detection or interpretation of the results from such instruments have resulted in better accuracy and reliability and have allowed remote sensing by digital or analog signals and readout. Air bubble capacitance can be made use of within electrically conducting liquids and battery powered units have been used for remote sensing of the inclination of ground level or the inclination of a vehicle such as an airplane or a spaceship with respect to both gravity and acceleration or deceleration. The flight level indicators used by aircraft make it possible to fly safely in bad weather when the level of a plane's wings with the horizon is otherwise undetectable and the direction of the earth easily confused by an aircraft pilot because of accelerative or centrifugal forces developed by the aircraft.
No previous tool for leveling having a completely detachable unit for resolving or sensing the inclination of a remote body so such body may be adjusted or leveled from a remote location is known to the present inventor, however. The present Applicant has therefore developed a level which can be used in the normal manner directly applied to a surface to detect inclination or which can alternatively be separated into two portions in electromagnetic or wireless communication with each other to detect the inclination of a remote surface and monitor it from a distance, or remotely. The usual arrangement will be to have the inclination detector placed upon the surface to be monitored and the receiver maintained with the worker or overall monitor. However, the invention also encompasses having a separable portion of the device be the inclination portion of the device or even to have both portions of the device, i.e. the detector and receiver separable from a main carrier in order to make the invention even more useful and adaptable to different or changing circumstances. Because of the fact that a larger leveling apparatus providing more extensive contact with the surface to be leveled or its inclination determined will usually provide more accurate results, other things being equal, it will usually be preferable to have the detector in a larger body and the receiver be contained in the separable body which takes a more compact size.
The present inventor is aware of the following prior patented art relating to inclinometers in general and more particularly, remote sensing inclinometers.
3. Description of Related Art
There have been a number of leveling or inclination devices developed through the years for indicating the level or inclination of a surface or structure or sometimes an opening or orifice in a structure from a distance when it is inconvenient, impossible, or sometimes dangerous for the one taking the measurement to be in the immediate viscidity of the level measurement apparatus or, rather frequently, to read the level instrument from. the position or angle available for such reading. Among such so-called remote reading instruments are the following.
Early U.S. Pat. No. 7,23,526 entitled “Leveling Staff” issued Mar. 24, 1903 to Hein, provided either the sound of a bell or the appearance of a light when a staff was properly aligned in an upright position for surveying purposes. The proper vertical alignment of such staff could therefore be determined from a distance.
U.S. Pat. No. 3,096,591 entitled “Radio Frequency Leveling Device” issued Jul. 9, 1963 to Higgins et al discloses the use of a capacitor circuit for detection of a bubble position in a spirit level thus converting the reading to a radio frequency signal suitable for remote signaling. The leveling device itself is not separable into a separate receiver and detector units, however.
U.S. Pat. No. 3,233,235 entitled “Signaling Level” issued Feb. 1, 1966 to G. Wright provided a leveling device operated electronically through a pendulum detection arrangement to detect the levelness of a surface upon which placed. A dial may be used to determine at what angle a reading may be signaled by an electrical signal providing an audible light or other signal so the results of the level operation can be detected from a distance allowing remote leveling at any given angle.
U.S. Pat. No. 3,324,564 entitled “Level with Electronically Responsive Instrument” issued Jun. 13, 1967 to Wright et al. discloses a level device which measures the change in reflectance of light from the bubble of a spirit level or in a light at the end of a pendulum reading the reflectance by dual capacitor plates and sending this signal through a circuit wire or cord to a meter unit connected to the detector enabling remote detection of leveling results.
U.S. Pat. No. 3,863,067 entitled “Orientation Indicating Apparatus” issued Jan. 28, 1975 to Gooley discloses an orientation detecting device using a bubble-type detector, the position of which bubble is detected electronically by reflected light and a signal, usually a light or auditory signal, issued for remote detection. It is mentioned in passing that such signals could be used to detect orientation at a distance remote from the detector, but no details are given, and a separate pod is not disclosed as being detectable from the main level casing for receiving a signal.
U.S. Pat. No. 4,154,000 entitled “Remote Level Sensing Instrument” issued May 15, 1979 to M. Kramer discloses means for improving the detection of a level surface by the application of electronic detection to a spirit level arrangement allowing remote detection and reporting of level or a particular inclined orientation. Various ways of increasing the accuracy of detection of the position of the bubble in a spirit level and using the results elsewhere are pointed out.
U.S. Pat. No. 4,467,527 entitled “Digital Read-Out Level” issued Aug. 28, 1984 to North et al. discloses a digital level unit that may be fitting into a carrier bar for remotely measuring angles and levelness of surfaces by the use of a level detector that may be removed and attached to different straight edge carriers for measuring surfaces. The level detector is based upon a weighted rotary member that is caused to rotate by the force of gravity by becoming aligned with the force of gravity and thereupon having its inclination with the straightedge carrier determined. The carrier is equipped with an automatic turn off switch to conserve battery power when the unit is laid aside.
U.S. Pat. No. 4,703,315 entitled “Level Indicating Device” issued Oct. 27, 1987 to Bein et al. discloses a leveling device, which is designed for remote indication of inclinations. The device is attachable to a main straightedge or the like and may include both an audible and visual signaling means to indicate a state of levelness or other angle at a distance or remote location.
U.S. Pat. No. 5,027,522 entitled “Electronic Level Indicator” issued Jul. 2, 1991 to Cagan et al. discloses an electronic level relying upon an electronic bridge circuit into which data from a bubble or spirit level or a pendulum level mechanism is fed, the resulting signal passes to a differential detector and ultimately to a suitable display. It is disclosed in passing that in order to provide low cost, the sensor may be constructed for replacement to allow easier replacement for repair, calibration, operational or production purposes. There is no intimation of having the leveling unit split into units for actual remote sensing of leveling or of removing certain elements for separate use in combination with the main unit.
U.S. Pat. No. 5,121,555 entitled “Proximity Differential Indicator for Aligning Machine Tools” issued Jun. 16, 1992 to Jiorle (the present inventor) discloses a device for quickly aligning a machine tool spindle to the work surface of the machine tool by use of paired inductive proximity sensors without touching the work piece.
U.S. Pat. No. 5,159,761 entitled “Electronic Level Indicator” issued Nov. 3, 1992 to Cagan et al. which is a continuation-in-part of the previous U.S. Patent to Cagan et al. adds a new FIG. 6 which illustrates the use of a level or inclination sensor having an additional bridge circuit for monitoring an additional level or inclination detector such that separate level or inclination data may be obtained in alternative directions. Such units may be directly plugged into or connected to the main unit and shown in separate readout units. The separate units are not separable from the main unit for detection, but only for multiplication of data or inclinations detected.
U.S. Pat. No. 6,836,972 entitled “Electronic Level with Audible and Visual Indicators” issued Jun. 4, 2005 to Drahos discloses a leveling device includable in a conventional spirit level or carpenter's level particularly for providing audible spoken transmission of the results obtained when in inaccessible or inconvenient places.
U.S. Pat. No. 7,154,406 entitled “Power Tool Level Indicator” issued Dec. 26, 2006 to Judge is designed for inclusion in the handle of an electric drill to indicate when in an equilibrium position.
U.S. Published Application 2007/0044334 to Leizerovich entitled “Wireless Device with Integrated Level” published Mar. 1, 2007 discloses broadly the combination of a hand-held cell phone or the like combined with a level which two units are operated separately, i.e. either as a communication device or as a leveler. The two functions do not appear to be integrated together in operation.
No prior art known to the Applicant discloses the use of a level which can be used in a normal direct reading manner, but has a separable module that can be removed from the level detector itself and receives level data by wireless communication where more convenient than direct reading of such information.